Using App Platform database env variables

@gabrielbottari 👋

The bindable variables are meant to be used directly in the values of environment variables that you define for your app components.

For example, you may just want to define your own environment variable called DATABASE_URL with value of ${db.DATABASE_URL}. The bindable reference of ${db.DATABASE_URL} will be replaced with the actual values when your app is deployed. The db prefix here is the name of my database component, so this would reference one of your own components.

You can input these bindable references directly in the UI where you enter environment variables, or if you’re working with a raw app spec YAML, you can include them directly in there. This is an example from our sample-golang-notes repo:

name: sample-golang-notes
services:
- name: web
  github:
    repo: digitalocean/sample-golang-notes
    branch: main
  envs:
  - key: DATABASE_URL
    value: ${db.DATABASE_URL}
databases:
- name: db
  engine: PG
  version: "12"

If your application code is in nodejs, then you would then access your environment variables as usual, depending on what name you’ve given them, with process.env.DATABASE_URL.